Phosphate

Suniland Magazine

1925

Florida's greatest single present source of mineral wealth is derived from her splendid deposits of phosphate, which she has visible supplies of at least 250,000,000 tons. The phosphate of Florida is known commercially as bone phosphate of lime, used throughout the world as the basis of all fertilizers. Phosphate rock is found in many sections of the world, the chief producing sections today being the French possessions of Tunis, Algeria, and Morocco, Makatea Island, the Dutch West Indies, Japan, Egypt, Australia and the United States, the last named country producing approximately half of the world's supply. Present production in the United States is confined practically to Florida and Tennessee, although what are believed to be the greatest deposits of phosphate rock yet uncovered in the world have been found in the Rocky Mountain regions of Idaho and Montana.

Two varieties of phosphate rock are found in Florida, namely hard rock and land pebble, the latter accounting for 90 per cent of the present production, this condition being attributable to the inability of the Florida producer of hard rock phosphate to compete with the Mediterranean product.

The developed hard rock deposits of Florida occupy a hundred mile narrow strip of land paralleling the Gulf Coast, stretching from Columbia County on the north to Hernando County on the south, Passing through portions of the counties of Alachua, Marion, and Citrus. Fifteen years ago hard rock production amounted to a half million tons a year, valued at nearly $5,000,000, but now the output has fallen to less than 200,000 tons, due to the fact that this product is at present entirely exported. It would stern, however, that the time will come when Florida hard phosphate rock will be used extensively in conjunction with lime for the upbuilding of Florida's less fertile soils.

Florida's pebble rock deposits are confined to the counties of Hillsboro and Polk, in what is known as the Bone Valley District. These mines at present are producing approximately 3,000,000 tons a year, valued at about $10,000,000 representing about 90 per cent of the total value of the phosphate industry of the state.

Phosphate mining in Florida is of the open pit method exclusively, the overburden being removed and the rock mined by hydraulic machinery, supplemented by mammoth dredges. The moving of the overburden is a colossal task, it being estimated that the phosphate companies of Florida remove more earth in a single year than were removed in the record excavation year in the building of the Panama Canal.

There has recently been placed in operation on Tampa Bay a $2,000,000 plant for the recovery of the finely divided phosphates that have heretofore gone to waste. Under this process the phosphoric acid is extracted and concentrated up to the strength necessary to combine it with other phosphate rocks, a process which its inventors claim permits them to produce a triple phosphate, the phosphate ammonia of which is available. There are millions upon millions of tons of finely divided phosphates in the old phosphate waste piles, and it is believed that a large portion of this supply will be recovered.